converter

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CLARKO

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john clarkson
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Hallo everyone

As recently posted iam now using a 75-300 for my bird photography, which is great but more range would be better. Another lens say a 400 is not in the budget.

Someone suggested a 1.6 converter, which would in practice give me a 450+

Can someone explain how this works, and how much effect it has on your shots.

cheers

john
 
A converter (aka Extender in Canon-speak, Teleconverter in Nikon-speak, or TC for short) is a little gadget that fits between your camera and your lens. It's like a sort of magnifying glass. The main results are that
  • :) you effectively magnify the focal length of your lens;
  • :( you decrease the maximum aperture at which your lens can work;
  • :( you decrease the image quality;
  • :( you may lose the ability to autofocus.

Canon make 1.4x and 2x TCs. Nikon make 1.4x, 1.7x and 2x. I guess the other camera manufacturers also make TCs with similar ranges but I don't know anything about them. There are also 3rd-party brands such as Kenko.

If you can fit a 1.4x TC onto your 75-300mm lens, it makes it 105-420mm. But if your lens is f/4-f/5.6, it becomes f/5.6-f/8. You may not be able to use autofocus at the long end.

If you can fit a 2x TC onto your 75-300mm lens, it makes it 150-600mm. But if your lens is f/4-f/5.6, it becomes f/8-f/11. You will definitely not be able to use autofocus at the long end.

TCs are really only designed to be used with long telephoto lenses and top-quality telephoto zooms. Canon and Nikon design their TCs so that they physically do not fit on anything other than the lenses they think are appropriate. Third-party manufacturers don't do that, so you might be able to fit a Kenko TC (say) onto a Canon lens which wouldn't accept a Canon TC. But if you manage to fit a TC onto a lens which the manufacturers don't recommend, the image quality is likely to be pretty awful.

With a 70-300 or 75-300 lens, I'd say it wouldn't be worth doing even if it were possible.
 
I have a Kenko 1.4 converter.
Manual focussing is required when the lens aperture is smaller than f4.5.
 
StewartR,

Would you think it'd be worth getting a TC for my 70-200 f/4?
 
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